Insecticidal substituted alkenes

ABSTRACT

wherein each of R1, R2 and R3 can be hydrogen or C1-C3 alkyl, and Z1 and Z2 separately can be hydrogen or halogen or together can be a carbon to carbon bond, and Y is thienyl, furyl, naphthyl, phenyl or phenyl substituted by one or two substituents selected from chloro, bromo, fluoro, carboethoxy, cyano, C1-C4 alkyl, C1-C3 alkoxy, nitro, methylenedioxy, ethylenedioxy, dimethylamino or diethylamino. A compound exemplary of my invention is 4,8-dimethyl-1-(3,4-methylenedioxyphenyl)-1,7nonadiene.   Novel 1,7-dienes and addition products thereof possessing juvenile hormone-like activity have been prepared. Such a compound is one having the formula

United States atent 1191 Leopold Dec. 2, 1975 1 INSECTICIDAL SUBSTITUTED ALKENES [75] Inventor: Eric Jan Leopold, Palo Alto, Calif.

[73] Assignee: Eli Lilly and Company, Indianapolis,

Ind.

[22] Filed: Apr. 27, 1973 [21] Appl. No.: 354,970

[52] US. Cl. 260/340.5; 260/332.2; 260/332.3; 260/332.5; 260/340.3; 260/347.4; 260/347.7; 260/347.8; 260/465; 260/469; 260/612;

[51] Int. Cl. C07D 317/50; CO7D 319/18 [58] Field of Search 260/340.5, 340.3

[56] References Cited OTHER PUBLICATIONS Gokhale et al. Chemical Abstracts Vol. 43 (1949) p. 1085.

Loev et al. Chemical Abstracts Vol. 51 (1957) pp. 1074-1075. Atal et al. Chemical Abstracts Vol. 69 (1968) p. 10150.

Primary ExaminerJames A. Patten Attorney, Agent, or Firm.loseph A. Jones; Everet F. Smith [57] ABSTRACT Novel 1,7-dienes and addition products thereof possessing juvenile hormone-like activity have been prepared. Such a compound is one having the formula 2 Claims. No Drawings 3,923,832 '1' 2 INSECTICIDAL SUBSTITUTED ALKENES DESCRIPTION OF THE PREFERRED EMBODIMENT BACKGROUND OF THE INVENTION The compounds of my invention are those having the My invention pertains to compounds which exhibit I following formula juvenile hormone-like activity. More particularly, the 5 12 compounds are characterized by a long carbon chain .'r containing at least eight carbon atoms to which is ati 2 tached a thiophene, furan, naphthalene, benzene or substituted benzene ring. wherein each of R, R and R is' independently hydro- It is well known that insect populations can be congen or a C -C alkyl 'group, Z and Z? are each sepatrolled by treating a metamorphic stage of the insect rately a hydrogen or a halogen, or taken together are a with a juvenile hormone to prevent passage of the incarbon to carbon bond, and Y is tliienyl, furyl, naphsect to a subsequent metamorphic stage. As a result of thyl, phenyl or phenyl substituted by one or two substitsuch treatment the insect will not achieve full maturity. nt from the group consisting of chloro, brOmO,

The structure of two such hormones, Juvenile Horfluoro, carboethoxy, cyano, C C, alkyl, C -C alkoxy,

mones I and II, are shown below. nitro, methylenedioxy, ethylenedioxy,"dimethylamino A series of synthetically prepared compounds having and diethylamino.

CH CH CH juvenile hormone-like activity are described in South For example, each of R, R?.-.and R may be such African Patent No. 67/5149. These compounds, like groups as methyl, ethyl -P PYL and P PY It is t the naturally occurring hormones, have a straight-chain be understood that all R groups need not be the same in carbon skeleton. This carbon skeleton is terminated by a particular molecule but that each R can take a value such groups as ester, hydroxy, halo, and amino. independent of the others. Z and Z taken separately Wigglesworth, J. Ins. PhysioL, 9, 105 (i963), recan each independently be hydrogen or halogen. Haloported that dendrolasin exhibits some juvenile horgens which may be employed include chlorine, bromone activity. Dendrolasin, a compound secreted by 40 mine, i di and flu rine, althoughchlorine is prethe mandibular gland of the ant, is 9-(2-furyl)-2,6- ferred. Z and 2 taken together'may be a carbon to dimethyl-2,6-nonadiene. carbon bond, in which event there is a double bond beln the course of synthetic studies in the diterpene setween the carbon atoms to which Z and Z are atries Nasipuri et al., J. Chem. $00., 1964, 2146, prepared tached. 9-(3-methoxyphenyl)-2,6-dimethyl-2,6-nonadiene by Y represents thienyl, furyl, naphthyl, phenyl or submeans of the Wittig reaction. There was no suggestion lituted phenyl, such as 4-cyanophenyl, 4-dimethat the compound possessed biological activity. thylaminophenyl, 3,4-dimethoxyphenyl, 4-carboethox- Schwarz et al., Life Sciences, l0, Part H, l 125 1971 yphenyl, 4-fluorophenyl, 4-isopropylphenyl, 3- synthesized a series of epoxidized terpenoid aromatic nitrophenyl, 4-ethylphenyl, 2-chloro-4-nitrophenyl, hybrids which exhibited activity as juvenile hormone 3,4-methylenedioxyphenyl, 2,6 dichlorophenyl or 4- i i methyl-2-nitrophenyl.

In US. Pat. No. 3,563,982, and pending application Representative of the compounds within the scope of Ser. No. 187,890, filed Oct. 8, 1971, various 2,6-dienes this invention are the following. v

are described as juvenile hormone mimics.

I have now discovered a class of compounds having juvenile hormone-like activity. My compounds comprise a hydrocarbon chain of at least eight carbon atoms, to which is attached a thiophene, furlan, naph- C|-i=CHCH,CHCH,CH,CH=C Cl-| thalene, benzene or substituted benzene ring.

CH CH CH -continued H CH. H

H CH H CH The preferred compounds of my invention are those chlorophenyl or 4-bromophenyl. The trans isomers of in which R, R and R are methyl or ethyl, Z nd Z the unsaturated compounds are preferred over the cis together are a carbon to carbon bond, and Y is 3,4- isomers. Particularly preferred are the compounds havmethylenedioxyphenyl, 3,4-ethylenedioxyphenyl, 4- ing the following Structures- Continued =(i-CH; a

scribed, to yield an appropriately substituted secondary alcohol. Ethyl ether is generally used as a solvent, although numerousmodifications to the well-known Grignard reaction are possible. For a discussion of some of the possible modifications of the Grignard syn- HOCHZCHg PICFHCPMCIFFC/Rn thesis, see M. S. Karasch and O. Reinmuth, Qrignard l R2 Reactions of No nmetallic Substances, Prentice-Hall Inc., New York, 1954. Wh.el'ein R2 and R3 have h ng p u y The final step in my process involves the dehydration scnbed, are lyur mg an be p pa y of the alcohol obtained in the second step to give the known procedures In the SClenllfiC l e 'al desired compounds possessing juvenile hormone-like The first step of my synthes1s involves the conversion properties. Dehydration may be accomplished by a deof such long cham alcohols as described above to a corhydrating agent in the presence of a hydrogen halide responding halo compound by replacing the hydroxyl acceptor that will not react with the dehydrating agent. group with a halogen, preferably bromine or chlorine. The halo enation ma be accom Shed b the use of A hydrogen hahde acceptor 1s a compound wh1ch w1ll rea ems i h as PB y PCl 6; G 11 remove the hydrogen halide generated during the reacth g c 3 9 enera y tion. Some examples are pyridine, sodium carbonate e halogenatlon 1s done 1n an aprot1c solvent such as d t n t h l P dichloroethane b t t hl M an er 1ary ammes, especia y net y amme. 088! e ,py me, car on erac or1 eorc 0 dehydratmg agents are H KHSO PBr P 0 and roform. One skllled 1n the art would real1ze, however, f bl 1 If I h] b that there are other t f th pre era y p-to uenesu ony c on e 1n t e presence poss1 e reagen s or e conver of pyrldme. The reactlon 1s convemently earned out by son of an aliphatic alcohol to an al1phat1c halide. I have 50 h o o eatmg between and C. for a period of one to had the most success usmg phosphorous tnbromide 1n five hours other rocedur S are al S o ossibl f r ex pyridine at temperatures between 20 and 10C. p e p 0 ample, the procedure of Traynehs et al., J. Org. Chem., The secmd Step my Process employs the well 27 2377 (1962) sin dim th lsulfox'de at C l nown Grignard coupling reaction. The aliphatic halu g e y l 1de obtained in step 1 is reacted with magnesium metal 55 My compounds can also be prepared by a method I to give the Grignard reagent which in turn reacts with shall refer to as the phosphonate route. This route is an aldehyde, Y-CHO, wherein Y is as previously dedepicted by the following equations.

ll CH2X CH2P(OR)2 (R0) 3P Q M Q 0 CHO In the equations above, X is chlorine or bromine, R is lower alkyl and Q represents one or two substituents chosen from chlorine, fluorine, bromine, carboethoxy, cyano, C,C alkyl, C -C alkoxy, nitro, methylenedioxy, ethylenedioxy, dimethylamino and diethylamino. The reaction sequence is stereoselective and gives almost exclusively trans isomer.

The first step in the phosphonate route is the wellknown Arbusov reaction forming a benzyl phosphonate through the reaction of an a-halotoluene with a trialkyl phosphite. Lower trialkyl phosphites (C -C are preferred, since the volatility of the by-product drives the reaction to completion. The reaction can be carried out in an aprotic solvent or neat, with heating between 70 and 150C, conveniently at the boiling point of the chosen trialkyl phosphite.

1n the second step of this route, the benzyl phosphonate obtained in the first step is reacted with an alkali metal hydride or amide, for example, sodium hydride, potassium hydride or lithium amide, and an aldehyde of the formula wherein R, R and R are as previously described. Such aldehydes are naturally occurring or can be prepared by known procedures in the scientific literature. The reaction can be carried out in various aprotic solvents, such as dimethoxyethane, tetrahydrofuran, dioxane, ethers, and benzene, by heating between 30 and 150C, conveniently at the boiling point of the reaction mixture.

The derivatives of the 1,7-diene addition products where Z and Z are hydrogen or halogen are prepared by various well-known procedures. The compounds wherein Z and Z is halogen are prepared by adding a halogen or hydrogen halide molecule across the double bond. The reaction is carried out in a solvent such as chloroform, carbon tetrachloride or ether in the cold.

The compounds wherein Z and Z both are hydrogens can be obtained by hydrogenation to reduce the double bond. The hydrogenation of carbon to carbon double bonds is well-known to those skilled in the art and may be accomplished in the presence of a proper hydrogenation catalyst. One such catalyst is palladium on carbon, although many other catalysts are possible. The reaction may be conducted at a temperature between and 100C. and at a pressure of up to 100 psig., preferably at between 20 to 40 psig.

The methods of preparing the compounds of my invention will be further illustrated by the following examples. Each example illustrates a separate step of the reaction sequence. It is to be understood that such examples are merely illustrative and are not intended to limit the scope of the invention in any manner.

8 EXAMPLE 1 To a solution of 156 g. (1.0 mole) of citronellol in 300 ml. of petroleum ether (b.p. 6971C.) and 25 ml. of dry pyridine at -lOC. was added a solution of 123 g. of phosphorous tribromide (0.50 mole) in 150 ml. petroleum ether dropwise at such a rate as to maintain the temperature with external cooling between 5 and 0C. The addition required about two hours and the mixture was stirred at 0C. for an additional two hours. The solution was poured into one liter of ice water and extracted three times with 300 ml. of petroleum ether. The organic extracts were washed with saturated sodium bicarbonate and saturated sodium chloride solutions and dried by passing the solution through a cone of anhydrous sodium sulfate. The petroleum ether was evaporated and the product was fractionally distilled to give 103 g. of citronellyl bromide, b.p. 8696C. at 5 mm. pressure. The product was identified by infrared and nuclear magnetic resonance spectroscopy (NMR).

EXAMPLE 2 Citronellyl magnesium bromide was prepared by the dropwise addition, under nitrogen, of a solution of 105 g. (0.46 mole) of citronellyl bromide in 300 ml. of anhydrous ethyl ether to 12.2 g. (0.5 mole) of elemental magnesium. Following the addition, the reaction mixture was heated at reflux for two hours. A solution of 69 g. (0.46 mole) of piperonal in 250 ml. of anhydrous ethyl ether was added slowly to the cooled Grignard reaction mixture. After the addition was completed, the mixture was heated at reflux for one hour and allowed to equilibrate slowly to room temperature. Saturated ammonium chloride solution ml.) was added to the mixture and the organic layer separated. The ether was washed with 200 ml. of 20 percent sodium bisulfite solution, followed by saturated sodium chloride solution, and dried over sodium sulfate. The ether was removed under reduced pressure. The compound obtained weighed 91.5 g. and was shown by NMR spectroscopy to be about percent pure 4,8-dimethyl-1-(3,4- methylenedioxyphenyl)-7-nonenyl-1-ol. The product was used in the next step without further purification.

EXAMPLE 3 To 14.5 g. (0.05 mole) of 4,8-dimethyl-1-(3,4- methylenedioxyphenyl)-7-nonenyl-1-ol in 75 ml. of dry pyridine was added 19.1 g. (0.1 mole) of p-toluenesulfonyl chloride in 75 ml. of dry pyridine with stirring. The mixture was heated at reflux for two hours and allowed to equilibrate slowly to room temperature. The mixture was poured over 300 ml. of ice water and extracted three times with 300 ml. of ethyl ether. The ether layer was washed with 2 N hydrochloric acid solution, saturated sodium chloride solution, saturated sodium bicarbonate solution and again with saturated sodium chloride solution. The ether layer was then dried over sodium sulfate and the solvent removed under reduced pressure to give 7.0 g. of crude 4,8- dimethyll 3 ,4-methylenedioxyphenyl )-l ,7-nonadiene.

The crude product was purified by chromatographing on a 400 by 45 mm. column containing g. of silica gel using petroleum ether as the eluent. A yield of 1.3 g. of the 4,8-dimethyl-l-(3,4-methylenedioxyphenyl)-l,7-nonadiene was obtained. The compound structure was confirmed by NMR spectroscopy.

9 EXAMPLE 4.

EXAMPLE for two and one-half hours. Citronellal (15.4 g., 0.1

mole) in 50 ml. of dimethoxyethane was added dropwise with stirring at room temperature. The reaction mixture was heated at reflux for three hours. Water (200 ml.) was added and the dimethoxyethane was removed at 50C. under reduced pressure. The remaining heterogenous mixture was extracted with ethyl ether and the resulting ether layer was washed with water and then with saturated sodium chloride solution and dried over magnesium sulfate. The solvent .was removed at.

reduced pressure to yield 25.0 g. of crude product which was purified by eluting it through a column containing 500 g. silica gel with petroleum ether. Nine grams of pure 4,8-dimethyl-1-(3,4-methylenedioxyphenyl)-l,7-nonadiene was obtained. The structure was confirmed by NMR spectroscopy. Gas chromatographic analysis indicated the compound to be 99 percent trans isomer and one percent cis isomer. Other compounds prepared by this method, including 4,8- dimethyll -(4-chlorophenyl)-l ,7-nonadiene, 4,8- dimethyl-l-(4-bromophenyl)-l,7-nonadiene and 4,8- dimethyl-l-(4-methoxyphenyl)-l,7-nonadiene, were also obtained as the pure trans isomers.

In a demonstration of the ability of my compounds to inhibit the maturation of insects, the compounds were applied topically to insects, at an early metamorphic stage, of four different species. The compounds were applied in acetone solution at concentrations of ten percent, one percent and 0.5 percent. One microliter of an acetone solution was applied to each test specimen. Each concentration was applied to ten test specimens of each species and compared to ten acetone controls and ten zero controls. Approximately eight to ten days later, the specimens were observed.

The insect species used in the test were Tenebrio molitor pupae; milkweed bug, fourth nymphal stage; wax moth, fifth larval stage; and Mexican bean beetle, fourth larval stage. At the completion of the test, each specimen was examined for the degree of its juvenile and adult characteristics. The milkweed bug, wax moth, and Mexican bean beetle were assigned a numerical rating ofO to 3 with 0 indicating no effect and 3 indicating the maximum effect or least adult development. Because of differences in morphology the Tenebrio rating scale was 0 to 4. In all cases a rating of 2 or higher means that the insect is incapable of reproduction. The number of specimens in each rating classification are given. The results for the compounds tested are summarized the following tables. In any test where the totaliof specimens reported is lessthan 10, those unreported died in some metamorphic stage. Such deaths indicate control, since the dead insects are not capable of reproducing.

trans4,8-Dimethyll 3,4-methylene dioxyphenyU-I .7-nonadiene Rating Insect Conc.,7z'- l 0 l 2 3 4 Tenebrio l0 I0 I l0 0.5 l0

acet l0 cont l0 MWB l0 10 acet l0 cont l0 WM l0 l0 1 l0 cont l0 M88 10 I0 I l0 0.5 l0

acet. l0

cont l0 trans-l-(4-Chlorophenyl)- 4,8-dimethyl-l ,7-nonadiene i Y Rating lnsect Conc. 0 l 2 3 4 Tenebrio 10 v I0 I l 3 1 l 5 0.5 7 2 l ace t. 9 cont 8 2 MWB l0 0 1 9 0.5 l0 acet 8 l cont 7 3 WM l0 l0 cont l0 MBB 1O 10 l [0 0.5 2 4 4 acet. 9 l

com. 10

trans-l-(4-Bromophenyl)- 4,8-dimethyl-l ,7-nonadiene Rating Insect Conc.,% 0 l 2 3 4 Tenebrio l0 10 l l l 7 0.5 l 2 7 acet. 9

cont. 9

MWB l0 10 l 10 0.5 l0 acet. 9 I

cont. l0

WM l0 l0 cont. l0

Continued trans-4,8-Dimethyll 3 ,4-methylenedioxyphenyl )-I ,7-nonadiene Rating I Insect Conc.,% l v 2 3 4 l 2 l 6 0.5 l 4 l 3 acct. l0

cont. I0

trans-l-(d-MethoxyphenyU- 4.8-dimethyll .7-nonadiene Rating Insect Conc..7( 0 2 3 4 Tenebrio l0 10 l 2 2 I l 0.5 8 2 acet. 9

cont. l0

MWB IO 7 l 6 l l 0.5 9 acet. l0 cont. l0

WM l0 l0 I I0 0.5 IO contv l0 MBB 10 l 9 l 7 3 0.5 7 l 2 acet. l0 com. l0

One important distinction between my novel l,7- nonadienes and previously reported 2,6-nonadienes as juvenile hormone mimics is the greater soil stability of the l,7-nonadienes. A stability study was run in a clay loam soil with the moisture content maintained at approximately 50 percent of field capacity. The test compounds, 2,6-dimethyl-9-(3,4-methylenedioxyphenyl)- 2,6-nonadiene [III] and 4,8-dimethyl-l-(3,4- methylenedioxyphenyl)-l,7-nonadiene [IV], were incorporated in the soil and analyzed by gas chromatography at various intervals over a one-month span. The percent trans isomers recovered are given in Table I. The trans isomers were used because they are the more active isomers, and the methods of preparation yielded either pure trans isomer or predominantly trans isomer.

TABLE l Ill Percent of trans Percent of trans Time lsomer Recovered lsomer Recovered 84.0 l07.2 3-Day 63.2 95.4 8'Day 15.9 74.8 l5-Day 4.5 50.5 2 I -Day l.4 29.8 28-Day 3.2 l9.5

wherein each of R, R and R is independently methyl or ethyl; Z and Z together are a carbon to carbon bond; and Y represents 3,4-methylenedioxyphenyl or 3,4-ethylenedioxyphenyl.

2. The compound of claim 1 wherein each of R, R a'ndR is methyl, Z and 2 together are a carbon to carbon bond, and Y is 3,4-methylenedioxyphenyl.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 3.923.832 Dated 12-2-75 InVe t Eric Jan Leopold It is certified that .error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 17, --a series of synthetically prepared compound having-- should appear below the drawings of Juvenile Hormones I and II.

Column 11, lines 2 and 3 "trans- 4,8-Dimethyl-1-(3,4

methylne-dioxyphenyU-l,7-nonadiene" should read --trans-1-(4-Bromophenyl) -4,8dimethyl-l, 7-nonadiene--.

Signed and Scaled this sixteenth 0f March 1976 [SEAL] Arrest:

RUTH C. MASON C. MARSHALL DANN Arlesting Officer Commissioner of Patents and.Trademarks 

1. A COMPOUND HAVING THE FORMULA
 2. The compound of claim 1 wherein each of R1, R2 and R3 is methyl, Z1 and Z2 together are a carbon to carbon bond, and Y is 3,4-methylenedioxyphenyl. 